The first glass used by humankind was obsidian, made naturally by the rapid cooling of molten rock in the throat of a volcano. Hard and durable, but easily worked by chipping and hammering, obsidian became the raw materials for scrapers, knives, spear points, and arrowheads 75,000 years ago. Superseded by metal impliments, obsidan tools and weapons passed into history, and it was only five thousand years ago that the Sumerians of...
Technical Papers
The SVS System - How it Works
A brief paper on the principles of AccuTru's self-validating temperature measurement system.
Type N Thermocouples
Dr. Noel Burley of the Australina Defense Command developed the Type N thermocouple in the 1970's. It is the most recent ISA Letter Designated Thermocouple having obtained letter designation in 1983. It was designed to minimize some of the instabilities of the conventional Chromel/Alumel Type K combination. It differs from Type K in the addition of Silicon in both the NP and NN wires and an increase in the Chromium...
Thermocouple Decalibration and Drift - Part I
Thermocouple Decalibration and Drift - Part II
Thermocouple Decalibration and Drift - Part III
Thermocouple Decalibration and Drift - Part IV
Thermocouple Decalibration and Drift - Part V
Thermocouple Decalibration and Drift - Part VI
White Papers
Self-Validation - How it Works
Thermocouples and RTD technology has been around for many years. It has been refined and extended to cover a broad range of temperature measurement needs. It is well documented that these contact temperature measurement devices experience "drift" or de-calibration while in service. For various reasons the sensor output can "drift" way from representing the true temperature. The magnitude fo the dirft depends upon sensor construction...
Reference Charts and Tables
EMF Output of Letter Desiginated Thermocouple Types
This chart displays the EMF curves for the various letter type thermocouples along the temperature scale
Thermocouple Response Times
This table provides response times for different sizes and various thermocouple tip types. The smaller the diameter the thermocouple, the faster the response time. An exposed tip provides a faster response than a grounded tip while the insulated tip thermocouple is still slower.
Characteristics of Thermocouples, RTDs, Infrared, and Thermisters
This table identifies the various characteristics of the four primary types of industrial temperature measurement devices. Helpful in determining the proper type of device for your application.
Melting Point of Selected Metals
The melting points of various metals can be helpful in selecting the proper thermocouple sheath materials for your application.
Designing a New or Improved Temperature Measurement System
The design of your temperature measurement system can play a significant role in the accuracy of your readings. This document contains a series of helpful hints when designing a new system or updating an existing system.
Temperature Conversion Guide
A helpful table for converting temperature readings from Celcius to Fahrenheit or from Farhrenheit to Celcius.
Recommended Thermocouple Temperature Ranges
The various letter type thermocouples are designed to cover a range of temperatures. Some have considerably lower limits than others. Selection of the type for measurement in the smallest possible range for your application assists in providing more accurate readings.
Thermocouple Color Coding/Tolerances
This table shows the various color coding combinations used to identify ther various letter type thermocouples along with data showing the special and standard limits of error for each type at various temperature ranges.
Upper Temperature Limits of Thermocouples Based on Diameter of Thermocouple
Although you may use very small diameter thermocouples at the upper temperature limits for that letter time, the life span of the thermocouple is considerably reduced. This table shows the maximum operating temperature that provides reasonable life for the various diameters.
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